Apparatus for removing high-bake enamel



Jan. 31, 1928 J. A. MILLER APPARATUS FOR REMOVING HIGH BAKE ENAMEL Filed April 1'? 1924 ENTOR 7%2 ATTORNEY Patented Jan. 31, 1928.

UNITED STATES OHN A. MILLER, or 'rAnnYrow v, new YORK.

.ar'ranarus non nnrrovnve" HIGH-BAKE ENAMEL.

Application filed April 17, 1924. Serial No. 707,109.

M Y invention relates to apparatus for removing high bake enamel from metallic articles.

To get a highly resistant, wear-resisting i surface on metallic automobile parts, such as fenders, engine hoods and the like, enamel is baked thereon at relatively high temperatures, say about 300 F. to 150 F.

When it becomes necessary to renew such I enamel for any cause, whether because of de fects occurring in the enameling process so that the part will not pass inspection, or whether the enamel has become scratched or injured from any cause, the high resistant i qualities of such baked on enamels become almost a defect in that the removal thereof, which must be efiected preparatory to re enameling, is very difficult, highly expensive, and time consuming. I

) Such enamel can be cheaply and readily removed by subjecting the metallic enameled part to asufliciently high temperature, say about 1000 F., for a period of time inthe neighborhood of 20 minutes, in about which time the enamel is substantially entirely burned off and disintegrated, so that such residue as may remain on the surface is Weak and of disintegrated character and can be readily removedas by a scratch brush, and

)the like. Q i y 1 The accompanying drawing illustrates an apparatus for burning off the enamel, which has been baked on the metallic parts at high temperatures. In said drawings, Fig. 1 is a a longitudinal section of an apparatus com= prising an electrical heater. Fig. 2 1s a fragmentary detail view showing the use of a flame heater, as a gas or oil heater, and Fig. 3 is a transverse section on line 3-8, Fig. 1.

i Reference character represents general ly a burning ofi oven of A type or inverted V type, which is heavily insulated as 1nd1cated at 12, so as to reduce the dissipation of heat to a minimum and to withstand tempera- 5 lanes in the neighborhood of 1000 F. Heat is supplied at substantially the highest part 14.- of the oven 10 from beneath, as, for can ample, by electric heaters 16 (Fig. 1), or by gas or oil burners 18 (Fig. 2). Due to the J tendency of heated air to rise, this elevated portion of the oven forms substantially an air pocket for the highly heated air. Baffle plates or heater guards 20 are placed over the heaters and serve to prevent the enamel 5 being burned off from running directly on to the heating devices and these guards or or other heating devices.

A conveyor chain traverses the oven 10 along the upper wall 32 thereof and is suitably supported as by the conveyor sheaves 34. The conveyor chain 30 is preferably returned outside the oven and preferably over the oven, as indicated at 36. A single chain conveyor may be used and when a two chain conveyor is used the chains are cross-connected by cross-bars 88. The return part ma run on sheaves or may slide overthe top of the oven in slides 40.

Means are provided for drlvmg the conveyor chain 30, as, for example, an electric I,

motor or equivalent driving device 42 may be utilized for this purpose and same is preferably arranged so that the conveyor can be operated intermittently, and in the form shown a clutch 4A, operated by a lever 46, is provided for such purpose and the drive is through the belt 48, worm 52 and worm gear 54 driving one of the conveyor sheaves 0r sprockets 3 1. Take up means are preferably provided to keep the conveyor comparatively taut and inthe form shown a weight 56 is used for this purpose, beingcarried by the lever 58, which is provided with sprockets 60 for engaging the conveyor chain on thereturn reach 36. The passage of air through the oven is preferably in reverse direction as compared with the movement of the conveyor. A blower 70 is shown to take the fumes and smoke out through the conduit 74 and discharge same through stack 76, and the connection of conduit 74: is. preferably made through the top wall of the oven near the conveyor inlet end. The travel of air through the oven is, of course, relatively slow, the blower being relied on principally to discharge smoke and fumes. If desired, inlet of air through the oven ends and particularly the conveyor inlet end may be closed during the burning ofl' treatment, as by locating the loading station in a room with doors which can be closed, or other arrangements may be resorted to. An emergency stack 78 may be fitted to the oven near the highest point thereof, and is provided with a damper 80, which is normally closed, but may be opened more or less as occasion for its use may arise.

To operate the apparatus, a batch of high bake enameled metallic parts, such as tenders 62, engine hoods 6st, and the like, are hung on the conveyor at the loading station 66, and power is turned on to operate the conveyor. Same is advanced to bring the parts loaded on at loading station 66 to the highest part or burning otl' station ll of the oven 10, and the motion of the conveyor is arrested. A new batch of parts can now be loaded on the conveyor at the loading station 66.

After the enameled parts have been held at the burning otf station 14. for a sufficient interval, usually about 20 minutes, the burning ad is complete, whereupon the conveyor is advanced to bring the parts as 62, 64, from the burning off station 14 to the unloading station 68, and to bring a new batch of parts from the loading station 66 to the burning oli'station 14L When the parts are taken oil at the unloading station 68, they are easily cleaned up with scratch brushes and the like and made ready for reenaineling treatment.

It will be seen that my invention affords an extremely rapid, effective, inexpensive and easy mode of restoring the original motallic surface of the parts and of removing enamel, whichbeing baked on at high temperatures is extremely resistant to ordinary treatment for coating removal, as by being passed through baths of pa nt remover and subjecting to scratching and similar operations for removal of the refractory coating.

I claim:

1., In apparatus for burning off high temperature baked enamel from metallic parts, anoven of the invertedVtype having its low down and portions open and its intermediate portion elevated to form substantially a hot air pocket, means for supplying heat to the highest part of the oven for burning off the baked on enamel, and guards for the heaters adapted to protect the heaters from the dripping or flowing enamel and also to permit upward passage of air through the heaters into the oven. p

2. In apparatus for lnirning oll enamel t'roiu metallic parts baked thereon at hi 'h temperatures, an open ended even of su stantially inverted V form, means for supplving to the highest part of the oven heat suliicient for burning off the baked on onamel, guard plates for the heating means, said guard plates overlapping one another from above downward and having their overlapping portions separated to provide air passages for the upward movement of the heated air.

In apparatus for burning ofi' baked on enamel from metallic parts, an oven having an elevated burning ofl' station therein, means for supplying heat to said burning otif station sufiieient to burn off the enamel from the metallic parts, a conveyor traversmg the said even and also having reaches e2;- tendiug outward from the oven at the opposite ends thereot, a loading station for enameled parts adjacent to th einlet end of the oven, an unloading station for the burned otij' partsat the exit end of the oven, and means for drawing on fumes from the oven 1 near the inlet end thereof.

4:. In apparatus for burning oli' enamel :t'roin metallic parts baked thereon at high temperatures, an open ended oven of sub, stantially inverted V form, means for supplying to the highest part of the oven heat suflicient for burning oil the baked onenamel, guard plates for the heating means, said guard plates overlapping one another from above downward and having their 9 overlapping portions separated to provide air passages for the upward movement of the heated air, and means for conveying the enameled parts through the oven.

In testimony whereof, I have signed my 9 name hereto.

JNO. A. MILLER. 

